This invention relates to airbag restraints for motor vehicle passengers and, more particularly, to an airbag-equipped side restraint for a motor vehicle passenger.
In general, it has been possible to design existing vehicle parts as deforming elements or to provide additional deforming elements for converting kinetic energy into deformation work in the longitudinal direction of a motor vehicle. The deformation path available in case of a broadside collision is known to be very limited. In the case of a side restraint for a motor vehicle passenger, therefore, the side-restraining device must be designed so that it has a transverse dimension sufficient for effective cushioning only when needed, i.e., in a broadside collision. U.S. Pat. No. 2,834,606 describes a side restraint which includes an airbag mounted in the region of a roof girder which, after being actuated by the driver in an impending accident, extends downwardly between a passenger and the sidewall of the vehicle. This side restraint does not result in passenger inconvenience with respect to room for movement during normal travel but, in case of an accident, the restraint extends like an air cushion between a passenger and the imperiled sidewall. In this known construction, however, too much time is required for the airbag to reach its working position after it is released because of the distance between the location of the stored airbag, i.e., in the region of a roof girder, and the pelvis-shoulder region of the passenger which is to be protected.
In addition, difficulties arise because the airbag must expand in the transverse direction of the vehicle but, after expansion, it may not be able to move into the space between the passenger's shoulder and the sidewall, which may be quite narrow.
These same disadvantages are exhibited by the protective device disclosed in U.S. Pat. No. 3,795,412 which forms a cage for the passenger suspended from the roof of the vehicle. In case of an accident, this cage is supposed to be extended downwardly to surround the passenger, including his seat, on all sides. For this purpose, the cage has inflatable hoses, aligned vertically and a web which extends between the inflatable hoses.
It is likewise known, as described in German Patent No. 34 22 263, to provide a reservoir, filled with a gaseous medium and mounted in a girder of a vehicle, which is connected through a valved line to an inflatable envelope extending along the roof frame. If the girder is deformed, causing a pressure increase in the reservoir, the envelope is inflated and then forms a head restraint for a passenger sitting next to this part of the roof frame. Aside from the fact that the length of the connecting line would probably cause difficulties with regard to rapid activation of the inflatable envelope, this device constitutes only a head restraint so that the passenger's body is left unprotected to deformations of the sidewalls, including the side door.
It should be noted at this point that, although release of the side restraint in the device described in the above-mentioned U.S. Pat. No. 2,834,606 is effected by driver actuation of a switch or the like, the prior art, such as German Offenlegungsschrift No. 2 212 190, also discloses automatic collision sensors which are arranged as strips extending about the vehicle. Other collision sensors work capacitively by detecting accident-caused deformation of an outer member of the sidewall such as described in European Patent No. 0 305 655 or by detecting the variation in distance between two deformation signal elements designed as light guides as disclosed in German Offenlegungsschrift No. 37 16 168.